Drive mechanism



T. F. LEDBETTER.

DRIVE MECHANISM.

APPLICATION FILED FEB. 16, I920 Patented Nov. 15, 1921..

2 SHEETS-$HEET 1.

memd Nov. 11.5, 1921.

2 SHEETS-S HEET 2.

T. F. LEDBETTER.

DRIVE MECHANISM.

APPLICATION FILED FEB. 1 s, r920.

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DRIVE mncnamsar.

Specification of Letters Patent. Patented N 15 1921 Application filed February 16, 1920. Serial No. 359,098.

. To all it may concern:

- Be it known that I, THOMASF. Lnonn'rrnn,

v a citizen. of the United States, residing at observed that the rent wheels are entirely (Jolumbus, in the county of Muscogee, and

State of Georgia, have invented new and useful Improvements in a Drive Mechanism, of which the following is a specification.

This invention relates to motor vehicles and more particularly to the provision of an improved drive mechanism. of the type in which both the front and rear'wheels are transmitted power from the motor.

In a prior Patent, No. 1,258,126, granted tome, there is shown an invention of this type which contemplates the provision of two distinct differential mechanisms, one for the front set of wheels and the other for the rear set of wheels. Moreover, in this prior I patent there is shown and claimed a specific form of front wheel drive construction in which the front wheel is located within a yoke pivotally connected to the front axle and is supported entirely by its drive shaft.

- The purpose of my present invention is to improve the drive mechanism shown in this priorpatent bythe provision ofa single differential mechanism for both the front and rear set of wheels and b materially altering the construction of the rent wheel drive. By an inspection of in prior patent it will be supported b their spindle -or drive shaft,

and should t is shaft become broken, the defect must be cured before the vehicle can be further used. Furthermore, it is desirable to eliminate the construction wherein a yoke extends over the wheels. I

' While the above are the two primary objects of my invention it' should be understood that I have numerous other objects of a similar character, such as the provision of a compact and durable differential structure which is very simple and efficient in operation.

. I am aware ofthe fact that it is oldin the art to provide a single differential which acts upon both the front and rear set of wheels, but so far as'I am aware, I am the first to disclose a differential for this purpose of the type which is hereinafter described. The above and other objects of my invention will-be come more apparent from areading of the following description, an inspection of the accompanying drawings, and a consideration of theappended claims, wherein f my invention is more specifically set forth rotary movement.

In the accompanying drawingsz Figure 1 1s a top plan view of the chassis of a'vehicle with my drive mechanism applied.

Fig. 2 is a horizontal cross sectional view of the differential mechanism, the axle housin being removed.

Fig. 3 is a sectional elevational view of a portion of the front wheel drive.

Referring .to the drawings more in detail, 10 indicates the chassis of a vehicle having any source of power M, such as an internal combustion engine or an electric motor, fromter two sets of pinions 16, 17. With the first set of pinions 16 there meshes a pair of miter gears 18, one gear being located on each side of the spider and suitably keyed or otherwise secured to the inner ends of the rear wheel shafts 13. It may be observed at this point that the hubs 18' of each of these gears extend in the direction of the ider and form together a bearing for the spiderin its Meshing with the outer set of pinions 17 is a pair of miter gears 19 arranged concentrically with the gears 18 on each side of the spider, and connected to the gears 19, or formed integrally therewith as shown, are hollow shafts 20 which fit about the rear wheel shafts 13 and have located upon them at their respective outer ends bevel pinions 21 as clearly indicated in Fig. 2. Secured to the spider arms and inclosing the pinions and miter gears is a housing 22 present instance it being-shown bolted, as at 27, to an exterior flange 28. It will be, of course, understood that this ring gear may be formed integrally with the housing andwithout involving a material change or al- 100. within openential'housingin any suitable manner, in the teration in the construction could be situated upon the interior thereof The power shaft 11 at the point where it meets the ring gear of the differential may have a bearing in the rear axle housing as at29, in which housing there are also bearings '30 and 31 for shafts 32 rovided with bevel gears 33 which mesh Wit the bevel pinions 21 and transmit power to the front wheels in a manner now to be described,

The shafts 32 have located therein) at points adjacent the front and rear wheel wheels, it will be observed that there is shown a front axle havinga central section], 1, and pivoted to this section are end axle:

sections 2 which have ears 3 each of whichrfit between two ears 4 formed upon arms 5 of the central axle section. Pivot pins 6 may be fitted through registering openings formed in-the ears 3 and 4 to complete the pivotal connection of the axle sections.

'.The front Wheels 7 are journaled upon the end axle sections 2 and ride; upon ball bearings shown in- Fig. 3, which have as their' outer races, washers 8, 8, and as their inner races, flan es 9 formed upon the interior of the wheel It will be noted that the outer race 8,is threaded upon the end of the axle and thus locks the wheel 7 upon its journal.

In order to transmit to the. front wheels the rotation of the shafts 32extending from the rear axle, these shafts 32 are provided at their forward ends with gears 36 meshing with bevel gears 37 fixedly secured in any suitable manner to the ends of shafts 38 having bearings39' in the central axte section and bearings 40 in the outer axle sections. In order to permit relative movement of, the 1tw o axle sections the shaft 38 has located therein a universal joint 41. This shaft may beconnected to the front wheels by means {of a hub cap 42 secured to the scription that I have disclosed a front wheel drive which is superior to that disclosed in my prior patent, and a differential cdnstruction which is extremely durable, simple, and compact in structure. The gears of this differential are all inclosed by the housing 22 to which the spider is secured and thus the differential will retain, for long periods of time, its lubricant withoutany assistance from the axle housingl vIt should further be understood that although I have described a specific form of front wheel construction, and a specific form of differential, such modifications may be made in these features and in the other parts of my drive mechanism as come within the scope of the appended claims.

What is claimed is:

-1. In a four wheel drive, a double differential mechanism for both front and rear wheels comprising a spider, two sets of bevel pinions arranged on the arms of the spider and at radially different distances from its center, a pair of gears, one on each sideof said spider, meshing with one of said sets of pinions, said pair of gears having hollow hubs, a'rear axle section fitting into driving relation with each ofvsaid hubs, a. second pair of outer gears concentric with'said first mentioned gears, arranged on each side of the spider and meshing with the other set of pinions, each of said last mentioned gears having an elongated hollow hub, a gear on ieach hub, driving connections between each hub gear and a front wheel, a rotatable housinginclosing said spider and gears and connected to said spider, and a ring gear on said housing, said housing having laterally extending portions inclosin the elongated hubs of said second pair 9 gears.

2. In a four wheel drive, a double differential mechanism for both front and rear wheels comprising a spider, two sets of bevel said spider, meshing with one ofsaid sets of pinions, said pair of gears having hollow wheel, as, by bolts 43, and having at its/hubs, a rear axle section fitting into driving relation with-each of said hubs, a second arms 46 which extend rearwardly therefrdm and may beconnected to the steering post in any usual manner.

my hand. .It should be'evident from the aboi e de pair of gears concentric with said first mentioned gears arranged on each side of the spider and meshing with the other set of pinions, each. of said last mentioned gears each'hub, driving connections between each hub gear and a front wheel, a rotatable having an elongated hollow hub, a gear on housinginclosing said spider and gears. and

connected to'said spider, and a/rmg gear on said /ho-sing. a

In testin ikay whereof I have hereunto set THOMAS/F. LEDBETTER. 

